QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

Earthquake near Richfield, UT

No earthquake was likely felt in Richfield in the 24 hours to 9:36 pm MST (04:36 UTC). The last one was M 3.2, 34 km (21 mi) W, at 8:35 am MDT on 22 April 2026, estimated intensity II (weak) in town; 6 felt reports to USGS. Every earthquake near Richfield

This page: a magnitude 1.8 earthquake was recorded 6 km (4 mi) southwest of Richfield, UT, at 11:50 am MDT on 13 October 2021 (17:50 UTC), 6.2 km deep.

USGS: 5 km NW of Central Valley, Utah

11:50 am MDT, Oct 13, 2021 · · 6.2 km deep · released about 14 lb of TNT

10 km30 km60 km120 km N Sevier County 29 kmPiute County 44 kmSanpete County 86 kmMillard County 89 kmBeaver County 104 kmWayne County 113 kmGarfield County 117 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
11:50 am MDT on 13 October 2021 ()
Where
6 km (4 mi) southwest of Richfield, UT · earthquakes near Richfield
Magnitude
M 1.8 (ml)
Depth
6.2 km below the surface
Felt
no reports yet
Nearest
Sevier County, 29 km E
Nearest mapped fault
Annabella graben faults, 10 km from its surface trace — near is not the same as on
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1856 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 12 km (7 mi) from the epicentre. In Richfield, 6 km away, the estimate is intensity II (weak). Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

Likely felt in: Richfield 6 km, intensity II · Monroe 12 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 14 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,100,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 760,000× the energy of this one
  3. Around the size people start to feel M 3.0 68× the energy of this one
  4. This earthquake M 1.8 about 14 lb of TNT

Energy from the Gutenberg–Richter relation (log10E = 1.5M + 4.8), rounded to two figures; bar length is magnitude, which is already a logarithm of energy. Magnitudes of past earthquakes from the USGS catalogue.

For this area

The largest earthquake within 50 km since 2016 was M 4.0 on 2019-02-20 — about 2,500 times the energy of this one.

Before 2016, the USGS record lists 4 earthquakes of M5 or more within 50 km:

  1. 6.6 Near Marysvale, Utah · 35 km SW of this epicentre
  2. 5.2 0 km SSW of Central Valley, Utah · 5 km SE of this epicentre
  3. 5.2 25 km SE of Salina, Utah · 46 km ENE of this epicentre
  4. 5.0 10 km NE of Marysvale, Utah · 25 km S of this epicentre

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Epicentre 38.7357, -112.1408. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Sevier County, UT 29 km (18 mi) E earthquakes near Sevier County
Piute County, UT 44 km (28 mi) S earthquakes near Piute County
Sanpete County, UT 86 km (53 mi) NE earthquakes near Sanpete County
Millard County, UT 89 km (56 mi) WNW earthquakes near Millard County
Beaver County, UT 104 km (65 mi) WSW earthquakes near Beaver County
Wayne County, UT 113 km (70 mi) ESE earthquakes near Wayne County

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

55 earthquakes have been recorded within 50 km since this one.

  1. 1.5 17 km W of Marysvale, Utah
  2. 1.8 24 km SSW of Kanosh, Utah
  3. 1.8 27 km SW of Kanosh, Utah
  4. 2.1 27 km SW of Kanosh, Utah
  5. 2.1 25 km SW of Kanosh, Utah
  6. 1.5 27 km SSW of Kanosh, Utah
  7. 1.5 27 km SW of Kanosh, Utah
  8. 2.1 20 km SSW of Kanosh, Utah
  9. 1.6 21 km SSW of Kanosh, Utah
  10. 1.6 22 km SSW of Kanosh, Utah
  11. 1.7 21 km SSW of Kanosh, Utah
  12. 1.9 7 km S of Kanosh, Utah
  13. 1.8 5 km WSW of Richfield, Utah
  14. 1.8 4 km WNW of Joseph, Utah
  15. 2.0 20 km W of Marysvale, Utah

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of . QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.